This invention relates generally to electric heating elements, and more particularly, to a new and improved electric heating element for insertion through a bulkhead of appliances such as dishwashers.
The use of heating elements in appliances such as dishwashers and the like is well known in the art. In many instances the heating element in the dishwasher has a variable heat range which is selectively energized between a low heat range and a high heat range. The low heat range of the heating element is used to dry dishes in the tub of the dishwasher after the dishes have been washed and rinsed. The high heat range of the heating element is used to raise the temperature of the water within the dishwasher to a high temperature and in some instances to a sterilization temperature.
The mounting of the heating element through the bulkhead of a dishwasher must withstand high temperatures. For example, the resistance heating element for the household dishwasher may have an output of a few hundred watts more or less when in exposed air for the drying of dishes and an output of 1000 to 2000 watts more or less when submerged to water for raising the temperature of the water. When utilizing heating elements of the resistance wire type, the temperatures within the dishwasher may reach as high as 170.degree. to 175.degree. F. Therefore, the mounting elements used to mount the heating unit to the bulkhead of a dishwasher must be able to withstand high temperatures.
Heretofore, resistance heating elements have been provided with a threaded fitting at their terminating ends. The threaded fitting may be of brass or the like and provided with an annular head or shoulder to overlie the peripheral margin of an aperture passing through the bulkhead of the dishwasher. A gasket is then positioned between the head of the threaded fitting and the bulkhead to provide a fluid-tight seal. A locking nut is threaded to the threaded member to firmly hold the heating element in position within the dishwasher, or other similar appliance. The heating element includes terminal electrical connecting wires extending from the threaded members so that electrical power can be applied thereto. The terminal connectors are usually maintained insulated from the threaded collar by a quantity of insulating epoxy or the like, as is well known in the art. The terminal connectors are known in the art as the cold wire end of the heating unit.
When utilizing a resistance heating element with the prior art type of mounting arrangement, substantial time and cost are involved in the manufacturing process of appliances. For example, it may require one operator to insert the heating element through the bulkhead from the inside of the dishwasher and another operator to make several separate connections at the exterior of the bulkhead. Therefore, the applying of the the threaded nuts to the threaded terminal ends and electrically connecting power lines to the terminal wires of the heating element are time-consuming and costly. Furthermore, special care must be taken in properly tightening the nut to the threaded end so that a fluid-tight seal is formed at the bulkhead of the appliance.